Abstract

Delamination between layers is a dangerous failure mode in fiber reinforced composite laminates. Pure
mode I tests were conducted to determine the interlaminar fracture toughness, using 16-ply DCB
specimens prepared from carbon/epoxy unidirectional fabric, under quasi-static condition. Analysis of the
test specimens in terms of mode I interlaminar critical strain energy release rate, GIc showed good
agreement between data reduction methods based on modified beam theory, compliance calibration, and
modified compliance calibration. The results showed that the measured GIc values at initiation for [0/90]4s
specimens are higher than that of unidirectional [00
]16 specimens.